<%--
  Created by IntelliJ IDEA.
  User: WuLiangHang
  Date: 2021/3/11
  Time: 10:16
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<%
    //往4个域中 保存key
    request.setAttribute("key", "request");
    pageContext.setAttribute("key", "pageContext");
    session.setAttribute("key", "session");
    application.setAttribute("key", "application");
%>
${key}
<%--
EL表达式 会按照四个域 从小到大的顺序进行搜索
--%>
</body>
</html>
